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Date: Sun, 18 Sep 1994 00:20:15 -0400 (EDT)
From: Robert.Patrick@cs.cmu.edu
To: postgres@postgres.Berkeley.EDU
Subject: Re: Last 'n' records?
In-Reply-To: <m0qlkES-0009C9C@dl6rai.muc.de>
References: <m0qlkES-0009C9C@dl6rai.muc.de>
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Excerpts from internet.postgres: 16-Sep-94 Last 'n' records? Bernhard
Buettner@DL6RAI (1441*)

> A problem arises with the fact that very often a user wants to  retrieve
> "the last 'n'" records of the database. Reading through the manual, I
> could not find an operator to do this. At this time, the query is
> realised as follows:

>      retrieve portal P unique (data.all) sort by date using >
>      fetch 5 in P

> This will take the whole relation, sort it by date and then retrieve the
> last 5 (0.01%). This cannot be the solution, but we can't find any
> better. Any hints, ideas?

The only solution (partial solution, anyway) I can see is to specify a
range on the dates so that only records with recent dates will be
retrieved.  If you really have 10,000 records/month, try limiting your
query to those records which match today's date (or yesterday's and
today's).




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